Symmetric Biomechanically Guided Prone-to-Supine Breast Image Registration

Prone-to-supine breast image registration has potential application in the fields of surgical and radiotherapy planning, image guided interventions, and multi-modal cancer diagnosis, staging, and therapy response prediction. However, breast image registration of three dimensional images acquired in different patient positions is a challenging problem, due to large deformations induced to the soft breast tissue caused by the change in gravity loading. We present a symmetric, biomechanical simulation based registration framework which aligns the images in a central, virtually unloaded configuration. The breast tissue is modelled as a neo-Hookean material and gravity is considered as the main source of deformation in the original images. In addition to gravity, our framework successively applies image derived forces directly into the unloading simulation in place of a subsequent image registration step. This results in a biomechanically constrained deformation. Using a finite difference scheme avoids an explicit meshing step and enables simulations to be performed directly in the image space. The explicit time integration scheme allows the motion at the interface between chest and breast to be constrained along the chest wall. The feasibility and accuracy of the approach presented here was assessed by measuring the target registration error (TRE) using a numerical phantom with known ground truth deformations, nine clinical prone MRI and supine CT image pairs, one clinical prone-supine CT image pair and four prone-supine MRI image pairs. The registration reduced the mean TRE for the numerical phantom experiment from initially 19.3 to 0.9 mm and the combined mean TRE for all fourteen clinical data sets from 69.7 to 5.6 mm

Surface Driven Biomechanical Breast Image Registration

Biomechanical modelling enables large deformation simulations of breast tissues under different loading conditions to be performed. Such simulations can be utilised to transform prone Magnetic Resonance (MR) images into a different patient position, such as upright or supine. We present a novel integration of biomechanical modelling with a surface registration algorithm which optimises the unknown material parameters of a biomechanical model and performs a subsequent regularised surface alignment. This allows deformations induced by effects other than gravity, such as those due to contact of the breast and MR coil, to be reversed. Correction displacements are applied to the biomechanical model enabling transformation of the original pre-surgical images to the corresponding target position. The algorithm is evaluated for the prone-to-supine case using prone MR images and the skin outline of supine Computed Tomography (CT) scans for three patients. A mean target registration error (TRE) of 10:9 mm for internal structures is achieved. For the prone-to-upright scenario, an optical 3D surface scan of one patient is used as a registration target and the nipple distances after alignment between the transformed MRI and the surface are 10:1 mm and 6:3 mm respectively

Improving the immunogenicity of native-like HIV-1 envelope trimers by hyperstabilization

The production of native-like recombinant versions of the HIV-1 envelope glycoprotein (Env) trimer requires overcoming the natural flexibility and instability of the complex. The engineered BG505 SOSIP.664 trimer mimics the structure and antigenicity of native Env. Here, we describe how the introduction of new disulfide bonds between the glycoprotein (gp)120 and gp41 subunits of SOSIP trimers of the BG505 and other genotypes improves their stability and antigenicity, reduces their conformational flexibility, and helps maintain them in the unliganded conformation. The resulting next-generation SOSIP.v5 trimers induce strong autologous tier-2 neutralizing antibody (NAb) responses in rabbits. In addition, the BG505 SOSIP.v6 trimers induced weak heterologous NAb responses against a subset of tier-2 viruses that were not elicited by the prototype BG505 SOSIP.664. These stabilization methods can be applied to trimers from multiple genotypes as components of multivalent vaccines aimed at inducing broadly NAbs (bNAbs)

Microbial diversity and biogeochemical cycling in soda lakes

Soda lakes contain high concentrations of sodium carbonates resulting in a stable elevated pH, which provide a unique habitat to a rich diversity of haloalkaliphilic bacteria and archaea. Both cultivation-dependent and -independent methods have aided the identification of key processes and genes in the microbially mediated carbon, nitrogen, and sulfur biogeochemical cycles in soda lakes. In order to survive in this extreme environment, haloalkaliphiles have developed various bioenergetic and structural adaptations to maintain pH homeostasis and intracellular osmotic pressure. The cultivation of a handful of strains has led to the isolation of a number of extremozymes, which allow the cell to perform enzymatic reactions at these extreme conditions. These enzymes potentially contribute to biotechnological applications. In addition, microbial species active in the sulfur cycle can be used for sulfur remediation purposes. Future research should combine both innovative culture methods and state-of-the-art ‘meta-omic’ techniques to gain a comprehensive understanding of the microbes that flourish in these extreme environments and the processes they mediate. Coupling the biogeochemical C, N, and S cycles and identifying where each process takes place on a spatial and temporal scale could unravel the interspecies relationships and thereby reveal more about the ecosystem dynamics of these enigmatic extreme environments

Tetrathionate turnover in marine sandy sediment

The turnover and ecological role of the sulfur intermediate tetrathionate (S 4 O 6 2- ) in the marine environment is still poorly understood. Tetrathionate turnover and its effect on bacterial growth in sandy sediment were investigated under anoxic and oxic conditions. Surface sediment was collected from Janssand, an intertidal sandflat in the German Wadden Sea, and fed with tetrathionate in packed flow through columns and batch experiments. A new High Performance Liquid Chromatography (HPLC) method was used to simultaneously determine tetrathionate and thiosulfate concentrations over time. Changes in the relative abundance of Bacteria, Gamma- and Deltaproteobacteria were analyzed with Fluorescence In Situ Hybridization with Catalyzed Reporter Deposition (CARD- FISH). It was shown that tetrathionate is consumed mainly by sediment-affiliated microbial communities both under oxic and anoxic conditions. Under oxic conditions, oxidation of tetrathionate is an important process and turnover rates exceed those in reduced sediments. With increasing oxygen limitation in the sediment pore-water, tetrathionate reduction, and to a lesser extent disproportionation, play an increasingly important role. Subsequent chemical degradation of the formed thiosulfate stagnates when the sediment becomes reduced. Although the ecological role of tetrathionate reduction, oxidation and disproportionation remains largely unanswered, fast and immediate turnover rates indicate that tetrathionate is an important intermediate in the marine sedimentary sulfur cycle

Two Case Presentations of Scapulothoracic Dissociation with a Range of Features and Approaches to Management: A 26-Year-Old Woman Injured in a Car Accident and a 52-YearOld Woman Injured While Cycling

Objective: Background: Case Reports: Conclusions: Rare disease Scapulothoracic dissociation (SD) is caused by a high-energy trauma that results in disruption of the scapulothoracic articulation, scapula and clavicular fracture, and severe neurovascular injury. This report describes 2 cases of traumatic SD with a range of features and approaches to management, a 26-year-old woman injured in a car accident and a 52-year-old woman injured while cycling. Case 1. A 26-year-old woman sustained an SD due to a car accident. A high index of suspicion led to the diagnosis, since there was a subtle clinical presentation. Open reduction and internal fixation (ORIF) of the clavicle was performed and the postoperative course was uncomplicated. Case 2. A 52-year-old woman was hit by a car while cycling and sustained multiple trauma injuries including a simultaneous brachial plexus injury and central cord syndrome, making the diagnosis of both entities a challenge. ORIF of the clavicle was performed and the brachial plexus was treated in a second stage. At the time of this report, the prognosis was poor. These cases have shown that the accurate diagnosis of SD requires a high index of suspicion and a detailed clinical examination and imaging, since there is a range of presentations and anatomic findings. Rapid treatment is crucial in preventing limb deformity and neurological damage and saving the patient’s life. © Am J Case Rep